DIY alternative to Evaporust

[Fawteen]

I expect most of us that turn wrenches much have heard of Evaporust. Works great, but it's like $30 a gallon and loses it's punch fairly quickly with use.

There's a DIY version that uses Citric Acid, Sodium Carbonate (washing soda) and water. A drop of dish detergent as a surfactant is optional.

Basically the Sodium Carbonate (a base) reacts with the Citric Acid to produce Sodium Citrate which is the active ingredient in Evaporust.

I mixed up a batch and tried it and it works perfectly. Somewhat more aggressive than Evaporust and alleged to last longer before neutralizing to the point that it won't work any more.

Used up the last batch so decided to make another. Here's the recipe:

One liter (a quart is close enough) of water
100 grams of citric acid (available from Amazon for ~$7.50 per pound)
40 grams of Sodium Carbonate (Arm & Hammer washing soda, also used for electrolysis)

The first batch, I did the water/acid/soda first, stirred until clear, added a drop of Dawn for a surfactant. Lovely.

Today, I thought I'd be clever, added a drop of Dawn to the water, added the citric acid, stirred until clear, then added the soda.

Holy Science Fair Volcano, Batman! The reaction between the soda and the acid is pretty impressive (think vinegar and baking soda) and the resultant bubbling got the Dawn ALL worked up! Wound up having to strain it through some gauze to keep the suds out of the container.

 

[Watthour]

A video clip will be required next time.

 

[Watthour]

BTW - What was the citric acid concentration?

 

[Fawteen]

BTW - What was the citric acid concentration?

Either I got that wrong (probable) or the price has changed, but it's 2 lbs for $9.95.

On Amazon

Concentration not specified.

 

[Absent Minded Farmer]

Citric Acid, Sodium Carbonate (washing soda)

Add some instant coffee to that & you can develop B&W film. It's one of a few developers that you can "pour on the ground" with little to no environmental impact. Good for dev'ing pics out in nature. Just adjust your times to the ambient temperature.

Mike

 

[Fixingfarmer]

The washing soda is good stuff my wife makes her own laundry soap and it is my go to for electrolysis as well

Salt into the dawn suds is what we did when tried it in the dishwasher (also not quite a volcano but a mess of suds all over the floor) after we ran out of the right soap but if you are going for rust removal salt is probably unwise

 

[drsportster]

Thank You I use a lot of that product Now I can save money

 

[John in Ct]

I just tried some CLR last week and to me, is working way faster than vinegar I used on a gas tank last year. I have stuff soaking as I type.

 

[john in la]

I turned this.



Into this.




With Citric Acid and washing soda.

 

[Jack345]

I turned this.

View attachment 135756

Into this.


View attachment 135761

With Citric Acid and washing soda.

John, thanks for super real life test, how long did it take & how much materials

 

[john in la]

John, thanks for super real life test, how long did it take & how much materials

I bought a 2 pound bag of acid for $10 on amazon. Found out this wasn’t getting anywhere so I bought another 5 lb bag for $20.


Mixed it up in a large ice chest.
I’d say the parts stayed in about 24 to 48 hours with 24 being the time for most parts.
The weaker you make it the longer it takes and the stronger you make it the less time it takes.
Plus the more pieces you run through the weaker it gets so the pieces take longer.
This did all the steel parts.

For the cast top I put it in another ice chest set up as an electrolysis unit. This worked ok after scrubbing it with a wire brush but I really wasn’t satisfied with the results. Maybe it was just taking too long for my taste. So I put the half finished top in the acid. It was pretty weak by this point but still worked.
Some final buffing with a scotch bright pad and some very fine sandpaper and you can see how the top came out. It’s still pitted and by no means a cabinet saw but works well for me. I got the saw for free. I recon I got less than $100 in paint all new bolts and acid in the project. I really don’t need the saw but it was a fun project now that I am stuck at home because of medical issues.

 

[showcrop]

The chemical manufacturer that I worked used a lot of Ethylenediaminetetraacetic acid in various detergents that I sold, to sequester calcium and magnesium, which of course makes water hard. Many of us use rust converter products like Corroseal and Ospho which are phosphoric acid based. The advantage to them is primarily that they convert rust to inert iron phosphate, which is the same coating as on your impact sockets. Phosphoric acid is readily available much more cheaply from food service supply stores where they sell it as limescale remover, and dairy supply stores where they sell it as milk stone remover. It dissolves rust and turns remaining rust into a black coating as you want.

 

[Dave G9N]

I recommend both the citric acid mix and milk stone remover. Citric acid to remove the bulk of the rust and milk stone remover optional for flash rust. The price of citric acid on Amazon varies all over the map, $0.23/oz for 10 lb bag and $0.18/oz for 50 lb. Citric acid will also clean your dishwasher and works to freshen the resin in the water softener.

I have tried the citric acid solution with very good results. It outlasts Evaporust and costs a lot less. It is reusable and will still remove a lot of rust long after it turns black. It will also clean copper alloys like brass and bronze, but if you do use it on copper alloys, do not reuse that solution on steel. The copper will plate out on the steel and if you leave it to soak, the copper will corrode the steel.

There is a Youtube video with the recipe for citric acid and baking soda, washing soda or lye. It explains a lot about the relative effectiveness of a number of rust remover products and the amount of corrosion caused by each along with the rust removed. One of the advantages of the citric acid mix and Evaporust is the lack of base metal removal compared to other solutions.

Pure citric acid is too acidic. Adding some soda reduces the acidity and works even better. Baking soda, washing soda and lye (sodium hydroxide) are all basically lye with different amounts of CO2, so it takes different amounts of each to make sodium citrate. The CO2 is heavy and is released when mixed, which is why it takes less lye than baking soda.

Component (Choose only 1 of the last 3)	Grams	Ounces by weight.
Water	1000 (1 liter)	133 (1 gallon)
Dish soap (Dawn is good)	some (add last or it foams!)	some
Citric acid	100	13
Washing soda (Na2CO3) OR:	40	5.3
Baking soda (NaHCO3) OR:	63	8.4
Lye (NaOH)	30	4

Milk stone remover is a mix of phosphoric acid, detergent and solvent that is very close to MIL-C-10587 Type I at a small fraction of the price. I like it and would recommend using it to provide a light iron phosphate coating after using the citric acid mix to provide some flash rusting resistance and a better paint base. The citric acid will remove a lot of rust and even some very hard mill scale without much etching of the base metal. Milk stone remover will remove the flash rust that forms rapidly after cleaning and can prevent flash rusting.

 

[RedMF40]

If you have small parts and some time on your hands drop them into pure vinegar in an old container you have lying around. Plastic is best. It'll strip heavy rust down to bare metal. Might not be practical for large areas as they have to be immersed in the vinegar.

 

[showcrop]

If you have small parts and some time on your hands drop them into pure vinegar in an old container you have lying around. Plastic is best. It'll strip heavy rust down to bare metal. Might not be practical for large areas as they have to be immersed in the vinegar.

"time on your hands" is key.

 

[NastySS]

Milk stone remover is a mix of phosphoric acid, detergent and solvent that is very close to MIL-C-10587 Type I at a small fraction of the price. I like it and would recommend using it to provide a light iron phosphate coating after using the citric acid mix to provide some flash rusting resistance and a better paint base. The citric acid will remove a lot of rust and even some very hard mill scale without much etching of the base metal. Milk stone remover will remove the flash rust that forms rapidly after cleaning and can prevent flash rusting.

I tried this concoction for the first time today and I'm blown away at it's effectiveness.One minor downside is the flash rust I got almost immediately.Do you use the milkstone remover full strength,and do you rinse it or let it air dry?Thanks!

 

[showcrop]

I tried this concoction for the first time today and I'm blown away at it's effectiveness.One minor downside is the flash rust I got almost immediately.Do you use the milkstone remover full strength,and do you rinse it or let it air dry?Thanks!

I have always brushed it on full strength, small parts I put in a bucket of 1/10 to soak. I always rinsed aggressively in water or pressure washer, because of the need to remove it from the areas that had no rust. I often get a little flash rust but it is just a faint very light amount, and I have never been concerned about it. I have always used it according to the process called for by "Rust Mort from SEM.

 

[SamV]

Very Interesting. I never knew you could make it!

 

[Mike(NEOhio)]

I haven't tried Fawteen's mix. Doing electrolysis now for the first time. I'm a fan of ER and agree it's pricey. I wire wheel as much loose rust as I can and use ER just to finish off the last of it. But I'll have to disagree that it's the same as Evaporust. All the other formulae are basically acidic. ER works through chelation to scavenge the iron from rust. It's non-acid and non-toxic.

 

[showcrop]

I haven't tried Fawteen's mix. Doing electrolysis now for the first time. I'm a fan of ER and agree it's pricey. I wire wheel as much loose rust as I can and use ER just to finish off the last of it. But I'll have to disagree that it's the same as Evaporust. All the other formulae are basically acidic. ER works through chelation to scavenge the iron from rust. It's non-acid and non-toxic.

You are correct about chelation. The manufacturer incorporated a lot of Ethylenediaminetetraacetic acid (EDTA) in various formulas.